Drive unit for motor dosing pump

Abstract

A drive unit for a motor metering pump and a metering pump, including a drive chamber and a drive shaft arranged in the drive chamber. The drive shaft is rotated about a longitudinal axis in a direction of rotation during operation of the drive unit, the drive unit includes a bearing in which the drive shaft is mounted. The drive chamber is filled with a lubricant up to a filling level during operation of the drive unit, and the bearing is arranged above the filling level in the direction of the longitudinal axis. The drive shaft has a conveying channel for the lubricant, which extends from a first point below the filling level to a second point above the filling level and is arranged in such a way that, during operation of the drive unit, lubricant is transported from the first point to the second point.

1 - 14 . (canceled) 
     
     
         15 . A drive unit for a motor metering pump, comprising a drive chamber and a drive shaft arranged in the drive chamber, wherein the drive shaft is rotated in a direction of rotation about a longitudinal axis during operation of the drive unit, wherein the drive unit comprises a bearing in which the drive shaft is mounted, wherein the drive chamber is filled with a lubricant up to a filling level during operation of the drive unit, wherein the bearing is arranged above the filling level in the direction of the longitudinal axis, wherein the drive shaft comprises a conveying channel for the lubricant which extends from a first point below the filling level to a second point above the filling level and is arranged such that during operation of the drive unit lubricant is transported from the first point to the second point, characterized in that the conveying channel is formed as a recess in an lateral surface of the drive shaft. 
     
     
         16 . The drive unit according to  claim 15 , wherein the conveying channel has a first boundary wall which delimits at least a section of the conveying channel in the radial direction, wherein preferably the conveying channel comprises a channel guide wall extending along the longitudinal axis or a channel guide wall inclined with respect to the longitudinal axis, and the first and a second boundary wall, wherein the first and the second boundary wall extend along the longitudinal axis and do not lie in a plane with the channel guide wall. 
     
     
         17 . The drive unit according to  claim 15 , wherein the drive shaft has a conveying section and a bearing section arranged in the direction of the longitudinal axis next to the conveying section and above the filling level, the conveying section projecting at least in sections in a radial direction with respect to the longitudinal axis beyond the bearing section, so that the conveying section has an upper surface and a lateral surface, wherein the upper surface forms an end of the conveying section facing the bearing section and is arranged above the filling level, wherein the conveying channel has an opening in the upper surface and an opening in the lateral surface, wherein the conveying section is configured such that when the drive shaft rotates in the direction of rotation, lubricant enters the conveying channel via the opening in the lateral surface and exits the conveying channel via the opening in the upper surface. 
     
     
         18 . The drive unit according to  claim 16 , wherein the channel guide wall is inclined relative to the longitudinal axis by a maximum of 85°, the inclination being such that, when the drive shaft is rotated in the direction of rotation, lubricant is lifted from the channel guide wall above the filling level. 
     
     
         19 . The drive unit according to  claim 18 , wherein the channel guide wall is delimited by the upper surface. 
     
     
         20 . The drive unit according to  claim 16 , wherein a first connecting section extending along the longitudinal axis is provided between the channel guide wall and the lateral boundary walls, wherein the first connecting section is curved with a radius of curvature, wherein preferably the lateral boundary walls are delimited by the lateral surface, and between the lateral boundary walls and the lateral surface a second connecting portion is provided which is curved with a radius of curvature. 
     
     
         21 . The drive unit according to  claim 16 , wherein the channel guide wall comprises at least two portions which enclose a different angle with the longitudinal axis, wherein preferably a portion of the channel guide wall spaced from the upper surface encloses a larger angle with the longitudinal axis than a portion of the channel guide wall ( 6   a ) adjacent to the upper surface. 
     
     
         22 . The drive unit according to  claim 16 , wherein the channel guide wall is convexly curved at least in sections. 
     
     
         23 . The drive unit according to  claim 17 , wherein the conveying section is cylindrical. 
     
     
         24 . The drive unit according to  claim 15 , wherein the drive shaft comprises two or more conveying channels, wherein a number N of conveying channels is preferably arranged around the longitudinal axis such that the drive shaft has an N-fold rotational symmetry. 
     
     
         25 . The drive unit according to  claim 15 , wherein the second point is arranged at most 50 mm above the filling level. 
     
     
         26 . The drive unit according to  claim 15 , wherein the bearing comprises a lower boundary surface arranged at an angle to the longitudinal axis, wherein the conveying channel ends at the lower boundary surface. 
     
     
         27 . The drive unit according to  claim 15 , wherein the drive shaft comprises an actuating member engaged with an eccentric for converting a rotational movement of the drive shaft into a translational movement, wherein the drive shaft further comprises a conveying section, wherein the conveying section is arranged along the longitudinal axis above the actuating member, wherein the conveying section comprises the conveying channel. 
     
     
         28 . A metering pump for conveying a fluid, comprising a displacement element and a metering chamber, wherein the displacement element delimits the metering chamber and is movable back and forth between a pressure position and a suction position, wherein a volume of the metering chamber in the pressure position of the displacement element is smaller than a volume of the metering chamber in the suction position of the displacement element, wherein a drive unit according to  claim 15  is provided, with which a drive force is applied to the displacement element during operation of the metering pump.